Your car has a vacuum leak or disconnected vacuum line. The
transmission's shifts are modulated by vacuum that's controlled by a
vacuum valve attached to the throttle linkage. The MORE the throttle is
opened the LESS vacuum is sent to the transmission's modulator. Light
throttle lots of vacuum, full throttle no vacuum.
Check the vacuum lines to and from the white? plastic valve that's
attached to the injection pump - at least it is on the 5 cylinder
engines, your six probably similar.
Noise is very subjective, fix the vacuum and then look underneath for
the noise. perhaps it's an exhaust leak.